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In order to clarify whether the myrosinase containes only thioglucosidase, or thioglucosidase and sulfatase, chromatographic behaviors of the myrosinase on cellulose ion exchanger were studied. Myrosinase showed two peaks by the chromatography on TEAE-cellulose at pH 8.5, but the fractionation of the two enzymes was not accomplished. It was concluded that the two peaks was not ascribable to an artifact but the two closely resembled species of myrosinase existing in the sample solution. Chromatographic separation of the two enzymes on DEAE-cellulose resulted in failure. These results confirmed that the myrosinase was a single β-thioglucosidase originally. 相似文献
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A characteristic effect of inorganic neutral salts on myrosinase was discovered. The salts containing monovalent anions had a remarkable inhibitory effect on the ascorbate-activated enzyme, but little on the non-activated enzyme. Such an effect was elucidated to be due to the anion. For the ascorbate-activated enzyme, a linear relation was obtained by plotting the logarithms of the enzymatic activity against the square roots of the ionic strength of the salts. Therefore, the effect of monovalent anions is ascribable to the ionic strength of the solvent. The Km values of the activated and non-activated enzyme were increased by the presence of the monovalent anion. 相似文献
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Masaru Ohtsuru Isao Tsuruo Tadao Hata 《Bioscience, biotechnology, and biochemistry》2013,77(9):1309-1325
In order to obtain fungous myrosinase, Aspergillus sydowi IFO 4284 was cultured on a medium containing mustard seed extract for 2 weeks. Myrosinase in the broth was purified about 150 fold by precipitation with ammonium sulfate and chromatography on DEAE-cellulose and DEAE-Sephadex. Comparison of thioglucosidase and sulfatase activities of the myrosinase preparation using pH-activity, pH-stability and temperature-stability curves revealed no differences from each other. The chromatograms of the two activities on DEAE-Sephadex showed good agreement. Consequently, the myrosinase produced by Aspergillus sydowi was concluded to be a single β-thioglucosidase, not a mixture of thioglucosidase and sulfatase.The effects of various reagents on Aspergillus sydowi myrosinase were studied.The enzymatic activity was stimulated by cobalt (II), zinc (II) and magnesium ions and inhibited by mercury (II), iron (II) and copper (II) ions. However, metal-complexing agents, SH reagents and diisopropylfluorophosphate showed no effects on enzymatic activity. In contrast to plant myrosinase, this enzyme was neither activated nor inhibited by any concentrations of l-ascorbate. Glucose and salicin were competitive inhibitors for the enzyme. High concentrations of sodium chloride inhibited the enzyme.From the inhibition modes of sugars and β-glucosides and from that of sodium chloride against the enzyme, a similarity of the enzyme to β-glucosidases was shown.β-Glucosidase activity of fungous myrosinase was confirmed using p-nitrophenyl β-glucoside as a substrate. This activity was revealed to be due to the myrosinase itself, Experimental results indicated a resemblance of fungous myrosinase to β-glucosidases similar to plant myrosinase. The relationship between fungous and plant myrosinases to the β-glucosidases are discussed from the view of the substrate specificity of these enzymes. The conclusions are that distinction between plant and fungous myrosinases and the β-glucosidases are not as strict as previously thought, and the myrosinases should be considered β-glucosidases highly specialized for the hydrolysis of mustard oil glucoside. 相似文献
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Crystalline yeast phosphoglyceric acid mutase is composed of several components. Though they have the same crystalline forms, the differences are found among their specific activities. Hereupon, it is necessary to elucidate the enzymatic properties of these components. As the results, the basic properties of each crystalline component have been found to be the same. 相似文献
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Ramavtar Sharma T. Mohapatra A. K. Mukherjee Krishanpal R. P. Sharma 《Journal of plant biochemistry and biotechnology.》1999,8(2):99-102
With the objective of identifying molecular markers for the seed oil content in mustard (Brassica juncea), which is known to be quantitatively inherited, 94 F6 generation recombinant inbred lines (RILs) developed from an intervarietal cross (Varuna × BEC144), were characterised. Oil content, determined by pulsed nuclear magnetic resonance technique, varied from 25.7% to 52.3% among the RILs. The frequency distribution of the trait was normal with mean 39.24 and standard deviation 4.52. Bulked segregant analysis of the RILs enabled fast and efficient screening of 219 random decamer primers for identification of informative primers. Single factor analysis of variance revealed significant association of oil content with three RAPD markers, viz., OPH111350, OPJ061200 and OPL05600 which individually explained 6% of the trait variance. Molecular data indicated dispersion of desirable quantitative trait loci in the two parent varieties. 相似文献
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The desmutagenic activity of various food components on C-nitro mutagens formed by the nitrite/sorbic acid reaction was assayed and several vegetable juices were found to be effective for eliminating the mutagenicity of the nitrite/sorbic acid system. Especially, the desmutagenic activity of pumpkin juice was investigated, and ascorbic acid, cysteine and other reducing compounds were found to be responsible for desmutagenic actions on 1,4-dinitro-2-methyl pyrrole, the main mutagen formed by the reaction of sorbic acid with sodium nitrite, by reduction of the conjugated C-nitro group to a C-amino group. 相似文献
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超干贮藏对芥兰种子生活力和活力的影响 总被引:3,自引:0,他引:3
1年的监测结果显示:芥兰种子开放贮藏时的生活力和活力下降最快,超干种子(含水量为4.91%、3.25%和2.84%)具有良好的耐藏性,其种子发芽率和简化活力指数增大,抗老化能力、超氧物歧化酶和过氧化氢酶的活性增强,膜进性降低,以2.84%含水量的芥兰种子贮藏效果为最好。 相似文献
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A protease from the lotus seed (Nelumbo nucifera Gaertn) was purified by acid-treatment, ammonium sulfate-fractionation, ethylalcohol-fractionation, TEAE-cellulose-treatment and Sephadex G-100 gel-filtration.The enzyme was purified about 870-fold and was homogeneous in electrophoretic and ultracentrifugal analyses.Purified lotus seed protease is an acid protease with a pH optimum at 3.8 toward urea-denatured casein. It is active for casein and hemoglobin. But other proteins such as edestin, zein, lotus seed globulin and soybean casein are slightly hydrolyzed and egg albumin is hardly hydrolyzed. This enzyme is most stable at pH 4.0 below 40°C. The enzyme is not a thiol protease, and its activity was completely inhibited by potassium permanganate, remarkably inhibited by sodium dodecylsulfate and accelerated by hydrogen peroxide. 相似文献
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Some physicochemical and enzymic properties of the purified lotus seed protease were investigated. The molecular weight determined from sedimentation-diffusion studies and by Sephadex G-100 gel-filtration was 36,800 and 35,500, respectively. The enzyme gave a typical ultraviolet spectrum of protein and its isoelectric point was found to be in a range of pH 3~4. The enzyme was stabilized at pH 6 in Tris-hydrochloric acid buffer by the addition of cupric ion. The inhibitory function of some reagents, especially that of potassium permanganate, and acetylation of the enzyme revealed that the tyosine residue in this enzyme protein might play some important role in the enzyme activity. Lotus seed protease was found to be fairly similar to pepsin in some properties. 相似文献
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Myrosinase in Sinapis alba L. 总被引:1,自引:0,他引:1
Extracts from developing seeds, seedings, and different organsof mature plants of Sinapis alba L. were tested for the presenceof myrosinase. Three different patterns of isoenzymes were distinguishedby isoelectric focusing. One was found in developing seeds andseedlings, a second in mature leaves, stems, flowers, and podsand a third in roots. Sections of all the parts tested were examined for the presenceof myrosin cells by light microscopy. Developing seeds and seedlingsshowed a good correlation between the appearance of myrosinaseand the presence of myrosin cells. No myrosin cells were foundin root or flower parts although they showed myrosinase activity. 相似文献
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A previous paper reported an investigation of myrosinase inthe seeds, seedlings and the different organs of mature plantsof Sinapis alba. The enzyme distribution was related to thehistological localization of myrosin cells. The present paperreports the situation for Raphanus sativus. Differences in myrosinasepatterns have been found but the two taxa are similar in thatthere is good evidence for the presence of the enzyme in myrosincells and in other non-specialized cells. Key words: Raphanus, Myrosinase, Isoelectric focusing, Myrosin cells 相似文献
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Carbonic Anhydrase,Photosynthesis, and Seed Yield in Mustard Plants Treated with Phytohormones 总被引:9,自引:0,他引:9
The leaves of 30-d-old plants of Brassica juncea Czern & Coss cv. Varuna were sprayed with 10–6 M aqueous solutions of indole-3-yl-acetic acid (IAA), gibberellic acid (GA3), kinetin (KIN), and abscisic acid (ABA) or 10–8 M of 28-homobrassinolide (HBR). All the phytohormones, except ABA, improved the vegetative growth and seed yield at harvest, compared with those sprayed with deionised water (control). HBR was most prominent in its effect, generating 32, 30, 36, 70, 25, and 29 % higher values for dry mass, chlorophyll content, carbonic anhydrase (E.C. 4.2.1.1) activity, and net photosynthetic rate in 60-d-old plants, pods per plant, and seed yield at harvest, over the control, respectively. The order of response to various hormones was HBR > GA3 > IAA > KIN > control > ABA. 相似文献
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Although a potent irreversible inhibitor of high-affinity choline transport in rat brain synaptosomes, choline mustard aziridinium ion (ChM Az) appeared to be a relatively weak inhibitor of choline acetyltransferase (ChAT) in rat brain homogenates, and evidence for irreversible binding of this compound to the enzyme had not been established. Accordingly, the irreversible inactivation of partially purified rat brain ChAT by ChM Az was studied. This compound is a rather weak inhibitor of the enzyme, with 50% inhibition of ChAT activity achieved following 30 min incubation at 37 degrees C with 0.6 mM ChM Az. This result indicates that although ChM Az has affinity for many nucleophiles there was little diluting effect of the inhibitor in the crude brain homogenate which could be attributed to such reactions (50% inhibition caused by 1.8 mM ChM Az following 10 min incubation). Although the initial binding of ChM Az to ChAT may be of a competitive nature, irreversible bond formation resulted. The time-dependent alkylation reaction conformed to pseudo-first-order kinetics with an observed forward rate constant (kobs) of 0.173 min-1; the half-time (t 1/2) for irreversible binding was about 4 min. The irreversible inactivation of ChAT by ChM Az would appear to be slower than the alkylation of high-affinity choline carriers in synaptosomes by this compound, and the relatively weak inhibitory action of ChM Az against either partially purified ChAT or ChAT activity in crude rat brain homogenates is in striking contrast to previous evidence that ChAT in intact synaptosomes was inhibited irreversibly by lower concentrations of the inhibitor. 相似文献
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A total storage protein fraction was prepared from mustard (Sinapis alba L.) seeds via isolated protein bodies and characterized by sedimentation, immunological, and electrophoretic techniques. Mustard seed storage protein consists of three fractions (1) a “legumin-like” 13-S complex composed of two pairs of disulfide-linked polypeptides (16.5 + 28.5 kDa and 19.5 + 34 kDa, respectively) and two single polypeptides (18 kDa and 26 kDa), (2) a “vicilin-like” 9-S complex composed of two glycoproteins (64 kDa and 77 kDa), and (3) two small polypeptides (10 kDa and 11 kDa) which probably represent the 1.7-S complex found in other Cruciferae. In contrast to related species, no glycosylated polypeptide was found in the 13-S complex. Immunological relationships were found between the paired polypeptides of the 13-S complex but not between polypeptides of the 13-S complex and polypeptides of the 9-S complex. Pulse-chase labeling and in vitro translation of polysomal RNA from young embryos demonstrated that the polypeptides of the 13-S complex originate from high molecular mass precursors, except for the 18 kDa polypeptide which appears to be synthesized in its final size. The amino-acid composition of the major polypeptides of the mustard storage protein is given. 相似文献